Hello all! I'm using version 7.2 of RESRAD-ONSITE to consider soil plutonium doses and corresponding risks. It is extremely common in the radiation epidemiology area to quantify risk via the 'excess relative risk', for example, for cancer morbidity (diagnosis of cancer), via

ERR = [(risk with radiation dose included) - (risk with no radiation dose)]/[risk with no radiation dose].

This has the advantage of being dimensionless (without units, since they cancel in numerator and denominator). As a consequence, you need not specify the risks directly (for example, as cases per 100,000 people). Within the linear, no-threshold description either the ERR or the excess risk are linearly proportional to radiation dose, of course.

To my astonishment, RESRAD claims to actually use (and prints out) the excess risk (ER = numerator of the ERR above), and I have found it difficult to discover the units--possibly per 100,000 people. Can some expert (i) confirm that RESRAD really DOES report the ER (NOT the ERR), and (ii) enlighten me about the units. Is there a document clearer than the user manual for version 7.2? THANKS!!